import argparse
import glob
import os
from pathlib import Path
import random
import string
import subprocess
from typing import Any, Dict, List


def get_args() -> Dict[str, Any]:
    parser = argparse.ArgumentParser(
        prog='video-to-gif',
        description='Use ffmpeg to make GIFs from videos',
        epilog='— Be gay and do crime')
    parser.add_argument('-i', '--input', type=str, required=True,
                        help="Input pattern like '/users/MyName/Videos/*.mov'")
    parser.add_argument('-w', '--width', type=str, default='960',
                        help='Width of the GIF in pixels, respecting aspect ratio')
    parser.add_argument('-r', '--framerate', type=str,
                        default='12', help='Framerate of GIF')
    parser.add_argument('-t', '--tag', type=str, default=get_tag(),
                        help='Optional tag included in file name')
    parser.add_argument('-f', '--force_palette', action='store_const',
                        const=True, help='Force regeneration of GIF color palettes')
    parser.add_argument('-c', '--clean_up', action='store_const',
                        const=True, help='Delete color palettes after finishing GIFs')
    return vars(parser.parse_args())


def get_tag() -> str:
    return ''.join(random.choices(string.ascii_uppercase + string.digits, k=5))


def get_inputs(args: Dict[str, Any]) -> List[str]:
    return glob.glob(args['input'])


def clean_up_palette_files(palette_map: Dict[str, str]) -> None:
    for input in palette_map:
        os.remove(palette_map[input])


def call_ffmpeg(command: str) -> str:
    print("ffmpeg", *command.split(' '))
    return str(subprocess.run(["ffmpeg", '-hide_banner', '-loglevel', 'error', *command.split(' ')]))


def generate_palette_files_and_map(inputs: List[str], args: Dict[str, Any]) -> Dict[str, str]:
    force_palette = args['force_palette']
    width = args['width']
    tag = args['tag']

    palette_map = {}
    for input in inputs:
        file_name = f"{Path(input).stem}_{tag}_palette.png"
        full_path = f"{Path(input).parent}/{file_name}"
        if force_palette or not os.path.exists(full_path):
            call_ffmpeg(
                f"-i {input} -lavfi scale={width}:-1,palettegen -sws_flags ewa_lanczos -y {full_path}")
        else:
            print(f"Skipped regenerating palette file {file_name}...")
        palette_map[input] = full_path

    return palette_map


def generate_gif_files(palette_map: Dict[str, str], args: Dict[str, Any]) -> Dict[str, str]:
    tag = args['tag']
    width = args['width']
    framerate = args['framerate']

    output_map = {}
    for input in palette_map:
        palette = palette_map[input]
        file_name = f"{Path(input).stem}_{tag}.gif"
        full_path = f"{Path(input).parent}/{file_name}"
        call_ffmpeg(f"-i {input} -i {palette} -f gif -r {framerate} -lavfi scale={ \
                    width}:-1,paletteuse -sws_flags ewa_lanczos {full_path}")
        output_map[input] = full_path

    return output_map


def make_gifs(args: Dict[str, Any]) -> None:
    clean_up = args['clean_up']
    inputs = get_inputs(args)

    palette_map = generate_palette_files_and_map(inputs, args)
    output_map = generate_gif_files(palette_map, args)

    if clean_up:
        clean_up_palette_files(palette_map)

    for input in output_map:
        print(f"Created {output_map[input]} from {input}")


def main() -> None:
    make_gifs(get_args())
    return


if __name__ == '__main__':
    main()